Concepts and usage of struct in C ++

What is a struct?

Simply put, a struct is a structure that can contain different data types. It is a data type that can be defined by itself. Its features are different from those of arrays, first, struct can declare different data types in a structure. Second, struct variables with the same structure can be assigned values to each other, but arrays cannot, because an array is a data set of a single data type, it is not a data type (while a struct is), and the array name is a constant pointer, it cannot be used as a left value for computation, therefore, arrays cannot be duplicated by array names, even if the data type and array size are identical.

Define the struct using the struct modifier, for example:

C ++Code Struct Test { Float; Int B; };

The code above defines a struct named test. Its data type is test. It contains two members, A and B. The data type of member A is floating point, the data type of member B is integer.

Since struct itself is a custom data type, the method for defining struct variables is the same as that for defining common variables.

Test pn1;

In this way, the pn1 struct variable of the test struct data type is defined, and the access of struct members is carried out through the vertex operator,

Pn1.a = 10 then assign values to member A of the struct variable pn1,

Note: The structure itself does not occupy any memory space during its life. The computer allocates memory only when you define the struct variable with the struct type you defined.

Struct can also define pointers. struct pointers are called structure pointers.

The structure pointer uses the-> symbol to access members. The following is a complete example of the above description:

C ++ code // Program author: Guan Ning // All manuscripts are copyrighted. To reprint them, be sure to indicate the source and author # include # include usingnamespacestd; structtest // defines a struct named test {< br> INTA; // defines struct member A intb; // define struct member B }; voidmain () {< br> testpn1; // define the struct variable pn1 testpn2; // define the struct variable pn2 pn2.a = 10; // use the member operator. assign a value to Member a in struct variable pn2 pn2. B = 3; // use the member operator. assign a value to Member B in the struct variable pn2 pn1 = pn2; // copy all the Member values of pn2 to the pn1 struct variable with the same structure cout cout test * point; // define the structure pointer point = & pn2; // The Pointer Points to the memory address of the struct variable pn2 cout point-> A = 99; // modify the value of pn2 member A in the structure pointer cout cout A <"|" B cin. get (); }

in short, a struct can describe a structure that is not clearly described by an array. It has some features that are not provided by an array.